Method of dynamically pre-fastening a disposable absorbent article having a slot-and-tab fastening system

ABSTRACT

A method and an apparatus for pre-fastening disposable absorbent articles having a slot-and-tab fastening system during manufacturing of the pre-fastened disposable articles, such as diapers, pull-on diapers, training pants, adults incontinence pads and the like.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of the parent application U.S. Ser.No. 10/036,633 filed on Dec. 21, 2001; U.S. Pat. No. 6,669,618.

FIELD OF THE INVENTION

The present invention relates to a high-speed-manufacturing method ofpre-fastening a disposable absorbent article having a slot-and-tabfastening system.

BACKGROUND

Disposable absorbent articles such as diapers, pull-on diapers, trainingpants, adults incontinence pads and the like, can include a fasteningsystem for joining the front of the article to the rear of the article.The fastening system can comprise a tab member and a slot memberdisclosed in U.S. patent application Ser. No. 09/143,184 filed on Aug.28, 1998, which is incorporated by reference herein. The disclosedfastening system is a refastenable fastening system that enables thewearer or the caretaker to refasten the article during the wear toprovide a more comfortable fit. The engagement of the tab and slotmembers can be done by the wearer or caretaker when securing the articlearound the wearer, or, alternatively, during manufacturing of thearticle to effect a pre-fasten article that is ready to be pulled on thewearer. Such manufacturing requires folding a normally flat-out articleinto a folded configuration and inserting the tab member into a slot ofthe slot member to form the pre-fastened article. However, themanufacturing of disposable absorbent article is normally a high-speedproduction wherein individual articles often move along a productionpath at a speed of hundreds feet per minute, and inserting the tabmember into the corresponding slot of the slot member at such highproduction speeds represents a problem.

Therefore, it would be beneficial to provide a high-speed-manufacturingmethod of pre-fastening a disposable absorbent article having aslot-and-tab fastening system to produce a pre-fastened absorbentarticle having engaged tab and slot members.

SUMMARY OF THE INVENTION

In response to the difficulties and problems discussed above, a newhigh-speed method of pre-fastening disposable absorbent articles duringmanufacturing of pre-fastened disposable absorbent articles having aslot-and-tab fastening system has been discovered.

The present invention concerns a method of dynamically pre-fasteningdisposable absorbent articles having a slot-and-tab fastening system asthe articles are driven forward at a relatively high velocity along apredetermined path. The method includes the step of providing adisposable absorbent article being folded longitudinally into a bi-foldconfiguration. The method further includes the step of inserting atleast a portion of a tab member of the slot-and-tab fastening systemthrough a slot of the slot-and-tab fastening system. And the methodfurther includes the step of while holding the portion of the tab memberbeing inserted through the slot, moving the slot member of the articleopposite to the direction of insertion of the portion of the tab memberuntil the slot of the slot member passes beyond a lip portion of the tabmember to effect a complete insertion of the tab member though the slotmember and to effect a closed configuration of the slot-and-tabfastening system forming a pre-fastened disposable absorbent article.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming the subject matter, which is regarded as thepresent invention, it is believed that the invention will be more fullyunderstood from the following description taken in conjunction with theaccompanying drawings, in which:

FIG. 1 is a plan view of a diaper having a fastening device comprising atab member and a slot member in its flat out, uncontracted state withthe body-facing surface oriented toward the viewer;

FIG. 2 is a perspective view of the diaper of FIG. 1, wherein the tabmember is engaged with the slot member by passing the tab member throughthe slot of the slot member;

FIG. 3 is a plan view of the slot member of the diaper of FIG. 1;

FIG. 4 is a plan view of the tab member of the diaper of FIG. 1;

FIG. 5 is a plan view of the engaged tab and slot members;

FIG. 6 is an end view of the engaged tab and slot members shown in FIG.5;

FIG. 7 is a simplified front elevation view of one embodiment of anapparatus of the present invention;

FIG. 7 a is a magnified, partial, front elevational view of the circledarea 7 a shown in FIG. 7;

FIG. 8 is fragmental, simplified side plan view taken along arrow 8 ofthe apparatus of FIG. 7, showing two slot locators;

FIG. 9 is a cross-sectional view, taken along lines 9—9, of the slotlocator shown in FIG. 8.

FIG. 10 is an enlarged view of circled area 10 of FIG. 7 a, showing thediaper in its instant position just prior to thrusting a leading part ofthe diaper pad against a stationary folding board of the apparatus ofthe present invention;

FIG. 11 is an enlarged view of circled area 11 of FIG. 7 a, showing thediaper in its instant position of thrusting the leading part of thediaper pad against the stationary folding board of the apparatus of thepresent invention;

FIG. 12 is an enlarged view of circled area 12 of FIG. 7 a, showing thediaper in its instant position having the tab member intercepted betweena guiding rail and the folding board;

FIG. 13 is an enlarged view of circled area 13 of FIG. 7 a, showing thediaper in its instant position of aligning the tab member with a slot ofthe slot member;

FIG. 14 is a cross-sectional view, taken along lines 14—14 in FIG. 13,showing alignment of the tab member with the slot of the slot member bythe guiding rail and the folding board;

FIG. 15 is an enlarged view of circled area 15 of FIG. 7 a, showing thediaper in its instant position of initially inserting the tab memberinto the slot of the slot member;

FIG. 16 is an enlarged view of circled area 16 of FIG. 7 a, showing thediaper in its instant position of further inserting the tab member intothe slot and attaching the inserted portion of the tab member to thedrum by a tab-clamping device;

FIG. 17 is cross-sectional view, taken along lines 17—17 in FIG. 16,illustrating the tab-clamping device attaching the tab member to thedrum;

FIG. 18 is an enlarged view of circled area 18 of FIG. 7 a, showing thediaper in its instant position of pulling off the diaper by a take-awayconveyor to complete the insertion of the tab member through the slot ofthe slot member to effect the engagement; and

FIG. 19 is a simplified front elevation view of another embodiment of anapparatus of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, the term “absorbent article” refers to devices, whichabsorb and contain body exudates and, more specifically, refers todevices that are placed against or in proximity to the body of thewearer to absorb and contain the various exudates discharged from thebody.

The term “disposable” is used herein to describe absorbent articles,which generally are not intended to be laundered or otherwise restoredor reused as absorbent articles (i.e., they are intended to be discardedafter a single use and, preferably, to be recycled, composted orotherwise discarded in an environmentally compatible manner).

The term “diaper” refers to an absorbent article generally worn byinfants and incontinent persons about the lower torso and typicallyhaving a fastening system to connect a back waist region with the frontwaist region in a closed configuration so as to provide lateral tensionsabout the circumference of the diaper to hold the diaper on the wearer.

The term “pre-fastened disposable article” or “pre-fastened article” or“pre-fastened diaper” refers herein to disposable absorbent articles,which are provided to consumer in a pre-fastened configuration of thefastening system (i.e., the fastening system is engaged to form aclosure) of the article and, which are intended to be put on the wearerthrough the legs of the wearer.

The terms “pull-on diaper” and/or “training pants” refer herein todisposable absorbent articles typically having a fixed, closedconfiguration around the waist of the wearer and, which are intended tobe put on the wearer by pulling the article through the legs of thewearer.

For ease of understanding, much of the following description withrespect to disposable absorbent articles comprising a slot-and tabfastening system will be made in terms of a diaper 20 disclosed in U.S.patent application Ser. No. 09/143,184 filed on Aug. 28, 1998, which isincorporated by reference herein.

FIG. 1 illustrates a plan view of one embodiment of the diaper 20 in itsflat-out, uncontracted state (i.e., with elastic induced contractionpulled out) including a slot-and-tab fastening system 40. The portion ofthe diaper 20 that faces or contacts the wearer, the inner surface 50,is oriented towards the viewer. As shown in FIG. 1, the diaper 20preferably comprises a liquid pervious topsheet 22; a liquid imperviousbacksheet 24 joined with the topsheet 22; an absorbent core 26positioned between the topsheet 22 and the backsheet 24; side panels 28;leg cuffs 32; a waist feature 30 and the slot-and-tab fastening system40.

The diaper 20 is shown in FIG. 1 to have an outer surface 52, an innersurface 50 opposed to the outer surface 52, first waist region 36, asecond waist region 38 opposed to the first waist region 36, a crotchregion 37 positioned between the first waist region 36 and the secondwaist region 38. The diaper 20 also has longitudinal edges 54 and endedges 56. The inner surface 50 of the diaper 20 generally comprises thatportion of the diaper 20 that is positioned adjacent to the wearer'sbody during use (i.e., the inner surface 50 generally is formed by atleast a portion of the topsheet 22 and other components joined to thetopsheet 22). The outer surface 52 generally comprises that portion ofthe diaper 20 that is positioned away from the wearer's body (i.e., theouter surface 52 generally is formed by at least a portion of thebacksheet 24 and other components joined to the backsheet 24). Thediaper 20 also has a longitudinal centerline 100 and a lateralcenterline 110.

The slot-and-tab fastening system 40 joins at least a portion of thefirst waist region 36 of the diaper 20 with at least a portion of thesecond waist region 38, preferably to form leg and waist openings. Asshown in FIGS. 1 and 2, the fastening system 40 can comprise a tabmember 42 and a slot member 44.

The slot member 44, shown in FIG. 3, includes an inboard portion 64attached to the side panel 28, an outboard portion 66 and a slot 46disposed between the inboard portion 64 and the outboard portion 66. Theslot 46 has a length S.

As shown in FIG. 5, the tab member 42 preferably includes a generallyelongate member having a length T, a proximal edge 60, a distal edge 62,a lip portion 48 generally adjacent at least a portion of the proximaledge 60. The length T of the tab member 42 should be sized to fitthrough the slot 46 of the slot member 44 with little or no bending ordeformation of either component. The lip portion 48 is that portion ofthe tab member 42 which is not joined directly to the underlyingstructure of the article to which the tab member 42 is attached. The lipportion 48 should lift away from the underlying structure of the articleso that it can be positioned in an overlapping configuration with atleast a portion of the outboard portion 66 of the slot member 44 when inuse (shown in FIGS. 5 and 6).

As shown in FIG. 6, the fastening system 40 can be fastened by passingthe tab member 42 completely through the slot 46 of the slot member 44.Once the tab member 42 has been passed through the slot member 44, asshown in FIGS. 7, the lip portion 48 of the tab member 42 is rotatedinto a plane generally parallel with the plane of the slot member 44such that at least a part of the lip portion 48 is overlapping at leasta part of the outboard portion 66 of the slot member 44. In thisconfiguration, the lip portion 48 of the tab member 42 will prevent thetab member 42 from slipping back through the slot 46 and disengaging thefastening system 40.

Referring to FIG. 1, the diaper 20 has a longitudinal centerline 100dividing the diaper 20 laterally equally between two opposinglongitudinal edges 54, and a lateral centerline 110 dividing the diaper20 longitudinally equally between two opposing end edges 56. The diaper20 also has fastening centerline 120 dividing the diaper 20longitudinally equally between the tab member 44 and the slot member 42so when the diaper 20 is folded along the fastening centerline 120, thetab member 42 and the slot 46 of the corresponding slot member 44 aregenerally aligned for at least partial insertion of the tab member 42into the slot 46. The fastening centerline 120 divides the diaper 20into a leading part 122 having the tab members 42 and a trailing part124 trailing the leading part 122 and having the slot members 44. Thefastening centerline 120 may or may not coincide with lateral centerline110.

The diaper 20 can be folded along the fastening centerline 120 into twoopposing parts with the topsheet 22 facing inside of the folded article20 (FIG. 2) and with the respective tab members 44 and slot members 42facing each other and properly aligned to form an engagement byinserting the tab member 44 through the slot 46 of the correspondingslot member 42 by a new process of the present invention. The newprocess can be provided by an apparatus 200, one embodiment of which isshown in FIG. 7 as a simplified, front elevation view. FIG. 8 shows afragmental, simplified side plan view of the apparatus 200 taken alongarrow 8 of FIG. 7. The new process is a dynamic process, meaning hereinthat the steps of the new process are performed when the apparatus 200is in motion, preferably at a predetermined velocity, which can rangefrom about 200 feet per minute to about 1,000 feet per minute.

Referring to FIGS. 1, 7 and 8, a web 202 preferably comprising amultiplicity of disposable absorbent articles 20, can move along apredetermined path 204 at a predetermined velocity 206. The web 202 canbe generally flat under tension directed in the direction of thepredetermined path 204. The articles 20 can be oriented in relation tothe predetermined path 204 such that the leading part 122 of the article20 leads the trailing part 124 of the article 20. The web 202 can bedeposited onto a peripheral surface 208 of an anvil roll 210 of a rotarycutter 212 such that the inner surface 50 of the diaper 20 is facing theperipheral surface 208 of the anvil roll 210. The web 202 can be heldflat against the peripheral surface 208 by an anvil roll holding force218, which can be provided by any suitable means including mechanicalclamps, belts, electrostatics, magnetism, vacuum and the like. In oneembodiment of the present invention, the anvil roll holding force can beprovided by vacuum communicating through openings in the peripheralsurface 208 of the anvil roll 210. The web 202, held flat against theperipheral surface of the anvil roll 210, can be cut into individualarticles 20 by a cutter 214 rotating with a cutter roll 216 of therotary cutter 212.

After the cut, the individual articles 20 can continue to be held flatagainst the peripheral surface 208 of the anvil roll 210 by the anvilroll holding force 218 until the individual articles 20 can betransferred onto a peripheral surface 220 of a drum 222 disposedadjacent the anvil roll 210 and rotating in the direction of thepredetermined path 204. During the transfer, the anvil roll holdingforce 218 can be turned off and a drum holding force 224 turned on tohold the individual article 20, now facing the peripheral surface 220 ofthe drum 222 with the outer surface 52 including the backsheet 24 of thearticle 20. The drum holding force 224 can be provided by the same meansas the anvil roll holding force 218 described herein above. In oneembodiment of the present invention, the drum holding force 224 can beprovided by vacuum communicating through the openings in the peripheralsurface 220 of the drum 222. Individual articles 20 can continue to beheld flat by the drum 222 under tension directed in the direction of thepredetermined path 204.

In addition to the drum holding force 224, the articles 20 can be heldto the peripheral surface 220 of the drum 222 along a fasteningcenterline 120 of the article 20, dividing the diaper 20 longitudinallyequally between the tab member 44 and the slot member 42, so when thediaper 20 is folded along the fastening centerline 120, the tab member42 and the slot 46 of the corresponding slot member 44 are generallyaligned for at least partial insertion of the tab member 42 into theslot 46. The article 20 can be held along the fastening centerline 120by any suitable means including a single continuous clamp or two or moreseparate clamps disposed along the fastening centerline 120. In oneembodiment of the present invention, the article 20 can be held by twocenterfold clamps 234 (see FIG. 8) disposed along the fasteningcenterline 120 for attaching the article 20 along the fasteningcenterline 120 to the peripheral surface 220 of the drum 222. Thecenter-fold clamps 234 can be activated by any suitable means capable ofattaching and detaching the article 20 along the fastening centerline120, including electro-mechanical, pneumatic, hydraulic, servomotors,cams and the like.

After depositing the article 20 onto the drum 222, the slots 46 of theslot members 44 of the article 20 can be located on the peripheralsurface 220 of the rotating drum 222 at a target position 230 by anysuitable mechanical device capable of engaging with the slots 46 andmoving the slots 46 transversely to the predetermined path 204 into thetarget position 230. The target position 230 is a position of the slotmember 44 on the peripheral surface 220 of the drum 220 suitable forengaging with the corresponding tab members 42 of the article 20. In oneembodiment of the present invention shown in FIGS. 8 and 9, each slot 46can be positioned into the target position 230 by a slot locator 232.The slot locator 232 can be actuated by any suitable means, includingelectro-mechanical, pneumatic, hydraulic, servomotors, and the like. Inone embodiment of the present invention shown in FIG. 9, the slotlocator 232 can be actuated by a cam (not shown) engaging a cam follower235 attached to the slot locator 232.

The apparatus 200 of the present invention can further include apeel-off roll 250 disposed adjacent the drum 222, preferably at a 6o'clock position of the drum 222, for separating the leading part 122 ofthe article 20 from the peripheral surface 220 of the drum 222 andtransferring the leading part 122 of the article 20 onto the peripheralsurface 252 of the peel-off roll 250. Prior to this, the leading part122 can be separated from the peripheral surface 220 of the drum 222 bydeactivating the drum holding force 224 under the leading part 122 ofthe article 20 and activating a drum separating force 236 under theleading part 122 of the article 20. The drum separating force 236 can beprovided by any suitable means including mechanical, electrostatic,magnetic and the like. In one embodiment of the present invention, thedrum separating force 236 can be provided by compressed air ventedthough the holes in the peripheral surface 220 of the drum 222.

After the leading part 122 is separated from the drum 222, the leadingpart 122 can be transferred onto and held against a peripheral surface252 of the peel-off roll 250 by means of a peel-off roll holding force254. The peel-off roll holding force 254 can be provided by the samemeans as the anvil roll holding force 218 described herein above. In oneembodiment of the present invention, the peel-off roll holding force 254can be provided by vacuum communicating through the openings in theperipheral surface 252 of the peel-off roll 250.

After the leading part 122, is transferred onto the peel-off roll 250,the peel-off roll holding force 254 can be substituted by a peel-offroll separating force 256, similar to the drum separating force 236,described herein above. The peel-off roll separating force 256 canseparate the leading part 122 from the peel-off roll 250, and acentrifugal force, resulting from the rotation of the drum 222, canextend the leading part 122 radially from the peripheral surface 220 ofthe drum 222. (See FIG. 10.)

Next, referring to FIG. 11, under continuing rotation of the drum 222,the leading part 222 extending from the peripheral surface 220 of thedrum 222 can move into contact with a stationary folding board 238situated along the predetermined path 204 to form a bi-foldconfiguration 21 of the diaper 20, wherein the article 20 is foldedlongitudinally. During the move into contact of the leading part 122with the folding board 238, each tab member 42 of the leading part 122folds at least partially around the folding board 238, preferably arounda longitudinal edge 240 of the folding board 238. Further, referring toFIG. 12, under continuing rotation of the drum 222, the tab member 42can pass between the longitudinal edge 240 and a stationary guiding rail242 disposed adjacent the longitudinal edge 240 and extending along thepredetermined path 204.

Further, under continuing rotation of the drum 222, the tab member 42being passed between the longitudinal edge 240 of the folding board 238and the guiding rail 242, can be guided by the longitudinal edge 240 ofthe folding board 238 and the guiding rail 242 to align the tab member242 with the slot 46 as shown in FIGS. 13 and 14, where FIG. 14 is across-sectional view taken along lines 14—14 of FIG. 13. (As describedherein above, the slot 46 has been aligned and held in the targetposition by the slot locator 132.)

Further, as shown in FIGS. 15 and 16, under continuing rotation of thedrum 222, the tab member 42 can be further guided by the longitudinaledge 240 of the folding board 238 and the guiding rail 242 to insert atleast a portion 47 (see FIG. 17 showing a cross-sectional view takenalong lines 17—17 of FIG. 16) of the tab member 42 through the slot 46of the article 20 into an opening 244 in the peripheral surface 220 ofthe drum 222. FIG. 17 also shows the next step of attaching the portion47 of the tab member 44 to the drum 222 by a clamp 246. As the slotlocator 232, described herein above, the clamp 246 can be actuated byany suitable means, including electro-mechanical, pneumatic, hydraulic,servomotors, and the like. In one embodiment shown in FIG. 17, the clamp246 can be actuated by a cam (not shown) engaging a cam follower 248attached to the clamp 246.

Further, while the portion 47 of the tab member 42 is clamped to thedrum 222, the article 20 can be partially lifted from the peripheralsurface 220 of the drum 222 (as shown in FIG. 18) by a conveyor 260, orany other suitable device, after deactivating the center-fold clamps 234releasing the article 20 along the fastening centerline 120, and alsoafter deactivating the drum holding force 224 releasing the trailingpart 124 of the article 20 from the peripheral surface 220 of the drum222. While the portion 47 of the tab member 42 continues to be attachedto the drum 222 by the clamp 246, the article 20 can be lifted from theperipheral surface 220 of the drum 222. By lifting the article 20, theslot 46 of the slot member 44 of the article 20 can move in relation tothe tab member 42 until the slot 46 passes beyond the lip portion 48 ofthe tab member 42. In this configuration, the lip portion 48 of the tabmember 42 will prevent the tab member 42 from slipping back through theslot 46 and disengaging the fastening system 40. After completing theengagement, the tab member 42 can be released from the drum 222 bydeactivating the clamp 246, and the conveyor 260 can complete liftingthe article 20 from the drum 222. The lifted article 20 can now have aclosed configuration 262 (see FIG. 2) of the slot-and-tab fastenersystem 40 forming a pre-fastened article 20. The conveyor 260 can thentransport the pre-fastened article 20 to downstream process operations.

Alternatively to the embodiment 200 shown in FIG. 7, wherein the web 202can be cut into individual articles 20 by the rotary cutter 212 prior todepositing the individual articles onto the peripheral surface 220 ofthe drum 222, FIG. 19 shows another embodiment 300 of the presentinvention. In the embodiment 300, the web 202 can be deposited onto andsecured to the peripheral surface 220 of the drum 222 and then cut intoindividual articles 20 by any suitable cutting device, for example, arotary cutter 310 cutting against the peripheral surface 220 of the drum222. The rest of the operations of the embodiment 300 can be the same asdescribed herein above for the embodiment 200.

While particular embodiments and/or individual features of the presentinvention have been illustrated and described, it would be obvious tothose skilled in the art that various other changes and modificationscan be made without departing from the spirit and scope of theinvention. Further, it should be apparent that all combinations of suchembodiments and features are possible and can result in preferredexecutions of the invention. Therefore, the appended claims are intendedto cover all such changes and modifications that are within the scope ofthis invention.

1. A method of dynamically pre-fastening disposable absorbent articleshaving a slot-and-tab fastening system as the articles are drivenforward at a relatively high velocity along a predetermined path, themethod comprising the steps of: (a) providing a disposable absorbentarticle being folded longitudinally into a bi-fold configuration; (b)inserting at least a portion of a tab member of the slot-and-tabfastening system through a slot of the slot-and-tab fastening system bypositioning the slot member with a slot locator and by guiding the tabmember with a guiding rail and a folding board; (c) while holding theportion of the tab member being inserted through the slot, moving theslot member of the article opposite to the direction of insertion of theportion of the tab member until the slot of the slot member passesbeyond a lip portion of the tab member to effect a complete insertion ofthe tab member through the slot member and to effect a closedconfiguration of the slot-and-tab fastening system forming apre-fastened disposable absorbent article, wherein the pre-fasteneddisposable absorbant article is traveling in a machine direction at arate of at least 200 feet per minute.
 2. The method according to claim 1wherein the pre-fastened disposable absorbent article is traveling at arate from about 200 feet per minute to about 1,000 feet per minute.